Controlling a duty cycle of a transmitter is generally known; but controlling the duty cycle of a transmitter of a portable, wireless, communications device, such as a pager or a cellular telephone, by a position of a cover or another part of the housing of the device is not known.
With portable, wireless communications devices having a cover, the immediate environment of the device is usually different depending upon whether the cover is in an opened position or in a closed position. When the cover is in the opened position, the device is usually being used; and, therefore, the immediate area around the device is clear, except for possibly being held in the a hand of a user. When the cover is in the closed position, the display and/or keyboard are not accessible to a user; and, therefore, the device is often in storage. The immediate area around the device when in storage is less likely to be clear of other objects; and, as a result of the other objects, the propagation of a signal transmitted by the device diminished. Often, the storage location, such as a mobile storage location, is only temporarily detrimental to propagation of transmitted radio signals.
For portable, wireless communications devices operating using a wireless, digital, time-division protocol, transmissions are made in one or more packets of information with each packet comprising a portion of a message. As a result, when the device in mobile storage location is temporarily in a weak signal condition, there is a great probability that, disadvantageously, none of the packets of information will be successfully transmitted. However, if the packets comprising a message were transmitted with a greater period of time between transmissions of packets, it is more likely that some of the packets would be successfully transmitted.
Thus, there is need to control the duty cycle in response to the position of the cover of the device, and thereby, indirectly, to control the duty cycle of the device when the device is likely to be in a storage location, in order to increase the probability that at least some of the packets be successfully transmitted.